Over the years there have been many fitness personalities who have created a big following and influenced many people. I've benefited from quite a few of these people over the last 20 years but the one guy who really stands out for me is Jeff Cavaliere of Athlean X. Jeff is incredibly knowledgeable and does not rely on "Bro-Science." He knows his stuff and is always in great condition but the thing I admire most about him is that he uses common sense which is not very common these days.
Sometimes his language can be a little colorful when he's trying to get a point across and he frequently struggles to keep his shirt on but he speaks the truth. If you are serious about improving your fitness or if you'd like to expand your exercise repetoire, I highly recommend him and his Youtube channel. He puts out so much good information on a regular basis and is head and shoulders above so many other Youtube trainers or fitness personalities.